Age-related changes in bioelectric activity of the trophotropic zone of hypothalamus in rats

Main Article Content

V. V. Mukvych
V. P. Lyashenko
S. M. Lukashov

Abstract

Introduction. Due to hypothalamus distribution into zones having no clear boundaries, its anterior and posterior parts are allocated, which, when irritated, exhibit directly opposite impaction the body. Instead, the changes in bioelectric activity of the trophotropic zone of hypothalamus in malerats of different age groups in normal conditions remain insufficiently studied. The withdrawal of bioelectric activity from the trophotropic zone of hypothalamus is in most cases the only indicator of determining the course of central nervous processes in the study of the functional state of the corresponding part of the brain.

Purpose. To identify age-related changes in bioelectric activity of the trophotropic zone of hypothalamus in male rats.

Methods. Experiments were carried out on non-linear white outbred male rats. The animals were distributed into studied groups using the classification of age groups of laboratory animals by Zapadniuk I.P. According to the classification male rats were divided into IV groups: I group (2.5 months) – the juvenile puberty period, II group (eight months) – the young age of the reproductive period, III group (fourteen months) – the mature age of the reproductive period, IV group (21 months) – rats of presenile age of the pronounced senile changes period (IV group). Rats of the studied groups underwent Electric Hypothalamus Test (EGtG) of the trophotropic zone. The corresponding hypothalamic zone bioelectric activity registration was carried out under the conditions of an acute experiment on a polygraph П6Ч-01 using standard electrophysiological equipment with a 16-bit analog-to-digital converter with a quantization frequency of 512 Hz (O.O. Bogomolets Institute of Physiology, Kyiv).

Results. In Juvenile male rats the highest percentage among other represented EGtG frequency components was the spectral power of the delta-range waves in trophotropic zone of hypothalamus. The males of the youngest age group showed the predominance of slow-wave synchronization processes in the form of predominance of low-frequency high-amplitude bioelectric activity in the trophotropic zone of hypothalamus. Instead, the age period changes resulted in significant changes indynamics of normalized spectral capacities of EGtG frequency components in the corresponding hypothalamus area. In young males, the functional activation of desinchronizing effect on bioelectric activity in this area of hypothalamus prevailed due to the predominance of the variation of the spectral power of the EGtG high-frequency components. Given the results of our study, where the highest percentage of alpha activity belongs precisely to rats of presenile age, this may be evidence of a certain peak in the brain maturation. However, in mature male rats, the prevalence of low-frequency oscillations and the predominance of delta-like activity in the EGtG, isolated from the trophotropic zone of the hypothalamus, which is evidence of the powerful synchronizing mechanisms functioning, were again observed.

Conclusion. It is shown that with age, the dynamics of normalized capacities of the EGtG frequency components in rats, isolated from the trophotropic zone of the hypothalamus, significantly changes. Registered age-related changes in the bioelectric activity of the trophotropic zone of hypothalamus of rats can be attributed to adaptive-compensatory modulation of central neurotransmission in general.

Article Details

Section
Статті

References

Zhurakіvska, O. Y. (2014). Age-related morphological changes of the hypothalamus ventromedial nucleus. Molodij vcheni (Young Scientist), 5 (08), 154-7 (in Ukr).

Bezrukov, V. V. (1982). The hypothalamus during aging. Physiological mechanisms of aging. Leningrad: Science; 94-107 (in Rus).

Frolkis, V. V. (1981). Aging. Neurohumoral mechanisms. Kiev: Scientific thought, 321 р. (in Ukr).

Musi, N. & Hornsby, P. (2015). Handbook of the Biology of Aging. 8-th edition. New York: Academic Press, 576 p.

Zayets, N. S. Lyashenko, V. P. Burtseva, D. O. Lukashov, S. M. & Melnіkova O. Z. (2014). Adaptive reactions of neyrosynaptycal activity of ergotropic area of the hypothalamus of rats in response to alkaline ration. Vchenі zapiski Tavrіjskogo nacіonalnogo unіversitetu іm. V. І. Vernadskogo. Serіja “Bіologіja, hіmіja” (Scientists note V.I. Vernadsky Taurida National University. Series “Biology, Chemistry”), 27, 46-55. (in Ukr).

Yoo, S. & Blackshaw, S. (2018). Regulation and function of neurogenesis in the adult mammalian hypothalamus. Progress in Neurobiologу, 54 (2), 71-88. doi: 10.1016/j.pneurobio.2018.04.001.

Lyashenko, V.P Melnikova, O.Z. Gorkovenko, A.V. Lukashov, S.M. & Chaus, T.G. (2007). Dynamics of characteristics of electrical activity of the tropho- and ergotropic zone of rats hypothalamus in the course of long-term emotional stress. Nejrofіzіologіja (Neurophysiology), 1, 69-80 (in Ukr).

Chaus, T.G Lyashenko, V.P. & Tkachenko, Y.O. (2015). General characteristics of electricactivity of rats’ hypothalamus under stress and suppression of catecholergic neuroconductibility with reserpine. Prirodnichij almanah (Natural almanac), 41, 167-82 (in Ukr).

Zadorozhnaya, G.A. Ljashenko, V.P. & Melnikova, O.Z. (2008) The influence of the vertical impulsive magnetic fields of right and left directions of rotation on hypothalamic bioelectric activity in rats. Fiziologicheskiĭ zhurnal (Fiziol Zh), 1, 91-00 (in Ukr).

Zapadnyuk, I.P. Zapadnyuk, E.A. & Zechariah E.A. (1983). Laboratory animals: breeding, housing, use in the experiment. Kiev: Vishha shkola; 383 p. (in Ukr).

Paxinos, G. & Watson, C. (2005). The rat brain in stereotaxic coordinates. 5-th edition. New York: Academic Press; 367 р.

Kinawy, A.A. Ezzat, A.R. & Al-Suwaigh B.R. (2014). Inhalation of air polluted with gasoline vapours alters the levels of amino acid neurotransmitters in the cerebral cortex, hippocampus, and hypothalamus of the rat. Exp Toxicol Pathol, 66 (5-6), 219-24. doi: 10.1016/j.etp.2014.02.001.

Falconi-Sobrinho, L.L. Anjos-Garcia, T.D. de Oliveira, R. & Coimbra, N.C. (2017). Decrease in NMDA receptor-signalling activity in the anterior cingulate cortex diminishes defensive behaviour and unconditioned fear-induced antinociception elicited by GABAergic tonic inhibition impairment in the posterior hypothalamus. Eur Neuropsychopharmacol, 27 (11), 1120-31.

Sharma, R.K. Choudhary, R.C. Reddy, M.K. Ray, A. & Ravi, K. (2015). Role of posterior hypothalamus in hypobaric hypoxia induced pulmonary edema. Respir Physiol Neurobiol, 205, 66-76. doi: 10.1016/j.resp.2014.10.010.

Melnikova, O.Z. & Lyashenko, V.P. (2009). Researches of mediator mechanisms of modulation at the terms of long duration stress of background total electric activity of ergotropic area of hypothalamus of rats. Uchenye zapiski Tavricheskogo nacionalnogo universiteta im. V. I. Vernadskogo. Serija “Biologija, himija” (Scientists note V.I. Vernadsky Taurida National University. Series “Biology, Chemistry”), 22 (61), 92-102.

Finnema, S.J. Scheinin, M. Shahid, M. Lehto, J. & Borroni, E. [et al.] (2015). Application of cross-species PET imaging to assess neurotransmitter release in brain. Psychopharmacology, 232 (21-22), 4129-57. doi: 10.1007/s00213-015-3938-6.

Vetrile, L.A. Zakharova, I.A. Kudrin, V.S. & Klodt, P.M. (2013). Effects of antiglutamate antibodies on the development of stress response and neurotransmitter content in the hippocampus and hypothalamus of rats with different behavioral activity. Bulletin of Experimental Biology and Medicine, 155(3), 318-23.